The telephone answering machine of the invention is generally similar to the telephone answering machine disclosed in U.S. Pat. No. 4,469,919. As described in that patent, present-day telephone answering machines often use two separate cassette-type tape drives. One tape drive is used to play back a pre-recorded outgoing message from one of the cassettes when a telephone call is received. The outgoing message typically states that the person is unable to come to the telephone and that a message may be recorded at the sound of a tone. When the caller hears the tone, he then dictates his messaoe into the telephone, and his message is recorded by the second or incoming message tape drive onto the second cassette tape.
After recording of the incoming message is completed, the incoming message tape drive stops. The answering device then reverts to an automatic answer mode and waits until a new incoming message is received at which time the outgoing announcement tape drive is activated and, subsequently, the incoming message tape drive is restarted. Each incoming message is sequentially recorded on the incoming message tape. To listen to the recorded messages, the user rewinds the incoming message tape to the beginning of the tape, and then places the second tape drive into a playback mode. The recorded messages are then sequentially played back in the order in which they were received.
It is often desirable to know the exact date and time that a particular message was received. The telephone answering machine disclosed in U.S. Pat. No. 4,469,919 is one which automatically records date and time information indicating when a message is received, and the machine displays the time and date as to that particular message, as the message is being played back. However, the telephone answering machine described in U.S. Pat. No. 4,469,919 requires two separate tracks for recording the incoming messages and the data indicating the date and time each such message was received. It is an objective of the present invention to provide an improved and simplified telephone answering machine in which the incoming messages and data relating to the date and time of each message are recorded on a single track.
Another objective of the invention is to provide such a system which may be constructed to produce a continuous display of the time at which each message was received for the duration of that message, as the messages are played back. Optionally, a second display may be used, or the first display may be switched to a second mode, to show the duration of the message being played back, in addition to the time at which the message was received.
Yet another objective of the invention is to provide such a system in which, during playback of the messages, time may be counted beginning with the time each message was received in a manner such that the actual message receiving time progresses in correspondence with the actual time progression during the time at which the call was recorded.
Yet another objective of the invention is to provide such a system which may be constructed so that, as the time duration of a message is displayed at the beginning of playback of that message, time is kept in a reverse counting condition so that the user may see the constantly reducing remaining time required for playback of the current message.
A still further objective of the invention is to provide such a machine, in which the data recording of the time of each message is kept in the microcomputer memory, and time data for the visual display is recovered in a sequential manner as each of the messages is played back in sequence, with the microcomputer using beep tones between the messages, or a special "mark tone" or a special data word containing the message number after each message. If a data word is used, the microcomputer records the data word subsequent to the incoming message without having to rewind the incoming message tape, thereby placing a sequential count after each message which may be correlated with the time stored in the random access memory of the microcomputer on subsequent playback.
Another object of the invention is to provide such a system in which the random access memory data is stored as described in the preceding paragraph on a specific location for subsequent retrieval by the microcomputer in the case of a power failure. This location, for example, may be at the beginning of the incoming message tape or at the end of the outgoing message tape.
Briefly stated, the telephone answering machine to be described is controlled by a microcomputer which includes a random access memory. In addition, a digital clock is included within the microcomputer using processed microcomputer timing, or an external clock may be used with appropriate interconnections.